Circuitry for controlling an electrostatic copier

ABSTRACT

A safety relay is serially connected with a manual switch for initiating operation of an electrostatic copier. A first contact of the relay maintains current in the relay coil, a second contact interconnects the power source with a high voltage generating source, and a third contact interconnects the power source with a discharge circuit. A two-position switch has a first position for connecting a voltage storage device to a power source and a second position for actuating a flash circuit. Another relay releases the safety relay with the two-position switch in the second position.

United States Patent Ogawa [15] 3,669,412 [4 1 June 13, 1972 [54]CIRCUITRY FOR CONTROLLING AN ELECTROSTATIC COPIER [72] Inventor: MasayaOgawa, Osaka, Japan [73] Assignee: Minolta Camera Kabushlld Kaislla [22]Filed: Dec. 22, 1969 2 u Appl. No.: 887,072

[30] Foreign Application Priority Data Dec. 31, 1968 Japan ..44/730 [52][1.8. CI ..3$5/3, 355/14 [51] Int.CI. .603; 15/00 [58] Field oiSearch..355/3. 10, ll, I4

[56] References Cited UNITED STATES PATENTS 3.424.526 1/1969 Sacre..355/l0 3,432,231 3/!969 Gardner ..355/ll X 3,358,570 l2/l967 Morrillet al ..355/l 4 3,503,677 3/l970 Uchiyama ....3$$/l4 UX 3,099,944 8/1963Eichorn et al. ..355/l4 3,397,627 SH 968 Bruning et al.... ...355/l 4 X3,266,366 8/l966 Hunt .355/l l X Primary Examiner-8amuel S. MatthewsAssistant Examiner-Robert P. Greiner Attorney-Watson, Cole. Grindle &Watson [57] ABSTRACT A safety relay is serially connected with a manualswitch for initiating operation of an electrostatic copier. A firstcontact of the relay maintains current in the relay coil. a secondcontact interconnects the power source with a high voltage generatingsource, and a third contact interconnects the power source with adischarge circuit. A two-position switch has a first position forconnecting a voltage storage device to a power source and a secondposition for actuating a flash circuit. Another relay releases thesafety relay with the two-position switch in the second position.

6 Clalns, 6 Drawing Figures PATENTEDJUR 13 late SHEET 10F 3 FIG.

I N VENTOR ATTORNEY PATENTEUJUN 13 I872 3,669,412

sum 2 0F 3 INVENTOR 416$; ,7 Mal/Q;

ATTORNEY PATENTED R 13 m2 3,669,412 sum 3 nr 3 FIG.5

INVENTOR 77/ 45' 9 BY Z7M- ATTORNEY CIRCUITRY FOR CONTROLLING ANELECTROSTATIC COPIER BACKGROUND OF THE INVENTION An electrostatic copieris provided with a charging device having a high voltage power source ashigh as several thousand volts, and makes use of a flash discharge tuberequiring a high voltage electric circuit. Prior art electrostaticcopier control circuits have not satisfactorily provided sufficientsafety to avoid operational mishaps.

SUMMARY OF THE INVENTION The present invention aims primarily to providea safety switch circuit for an electrostatic copier control circuit,wherein a safety switch circuit opened in synchronism with the exposureis provided in series with a power switch.

The primary object of the present invention is to provide anelectrostatic copier with a safety switch circuit opened in synchronismwith the exposure of a given number of copying sheets in order to carryout successive copying.

Another object of the present invention is to provide a safety switchclosed manually and opened in synchronism with the exposure ofa copy,and a set switch for a number of copying sheets, so as to carry outsuccessive copying from one to several sheets and to stop the operationof the high voltage power source generating circuit in synchronism withthe exposure for the successive copying.

A further object of the present invention is to provide an electrostaticcopier adapted to operate the driving circuit of a motor by means of thesafety switch circuit so as to operate a delivery motor for delivering aphotosensitive paper from a photosensitive paper stack in succession tothe exposure station while the safety switch circuit is closing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side view showing theessential parts of an electrostatic copier of an embodiment inaccordance with the present invention.

FIG. 2 is an enlarged perspective view of the original irradiationportion of the electrostatic copier.

FIG. 3 is a circuit diagram of an embodiment in accordance with thepresent invention.

FIG. 4 is a circuit diagram of another embodiment of the presentinvention, which is provided with a safety switch circuit added with aswitch for setting up number of copying sheets.

FIG. 5 is a perspective view of the switch for setting up the numberofcopying sheets in the embodiment of FIG. 4.

FIG. 6 is a circuit diagram of the safety switch circuit of anotherembodiment in accordance with the present inventron.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. l, in copier case body Ithere are disposed original irradiation portion A, copying portion B,photosensitive paper stack C, charging portion D, developing portion E,and drying and fixing portion F.

Original irradiation portion A is provided in contact with the topsurface of case body I as shown in FIG. 2 and composed of body 4 havingflat glass 3, on the surface of which original 2 is placed. Body 4 isprovided on its bottom surface with aperture 5 for emitting light raysof an image of original 2, however, except for aperture 5 body 4 islight tight to prevent the internal light rays from leaking and providedwith two flash discharge tubes 6 on both sides inside thereof forilluminating the whole surface of the original instantaneously. Theinside of body 4 is formed with irregular reflection surfaces so as tobetter reflect light rays. And, as shown in FIG. 1, on flat glass 3there is provided cover 7 for holding down original 2 onto case body 1.

Right below aperture 5 there is provided reflector 8 disposed at anangle of 45 degrees so as to reflect light rays of an image of original2. On the optical axis of reflector 8 there is provided copying lens 9in copying portion 5 to form an image oforiginal 2 onto image formingsurface 10.

Lens 9' is a copying lens for changing the magnification andinterchangeable with copying lens 9 as occasion demands so as to form adifferent magnification in the same way as copying lens 9.

Photosensitive paper stack C is disposed on the upper portion of casebody I, and in the interior thereof a large number of photosensitivepapers are piled up on loading plate 12 so that the photosensitive paperon the upmost position is always in contact with delivery roller 14 bybeing pressed upward by spring I3.

Reference numeral 15 denotes forwarding rollers which forward aphotosensitive paper delivered to charging portion D, and roller 14 isdriven by delivery motor 16.

Charging portion D is composed of two corona discharge devices l7, 18facing each other, as well known in the prior art, to give a uniformcharging to photosensitive papers delivered one after another.

Reference numeral 19 is a conveyor which transports the photosensitivepaper to the copying portion and is driven by a number of carrierrollers 21,, 2],, 21 21,, driven by carrier motor 20. Rollers 21 and 21,are disposed vertically on the extension of image forming surface I0 ofcopying portion B. Facing image forming surface, and on the back ofconveyor 9, there is disposed air suction mechanism 22 for holdingphotosensitive paper onto conveyor 9.

Developing portion E is composed of developing tank 23 for developingthe photosensitive paper transported from carrier roller 21,, developerreservoir 24 located under developing tank 23, pump 26 driven by motor25, pipe 27 for drawing the developer through pump 26 to developing tank23, and pipe 28 for returning the overflowing developer to reservoir 24,and arranged to develop the photosensitive paper by adsorbing wet toneronto the photosensitive paper on which an electrostatic latent image oforiginal 2 is formed, as it passes through image forming surface 10.

The developed photosensitive paper is transported to drying and fixingportion F by belt 29 and applied to the drying air heated by fan 30 andheater 3] and discharged to tray 32.

On the entrance of the photosensitive paper on image forming surface 10there are provided two switches 33, 34 in parallel. When the end of thephotosensitive paper is sent in switch 33 is opened to shut off thecircuit of delivery motor I6. Switch 34 is a charge and discharge changeover switch to a condenser for operating a switch mechanism describedhereinafter, which is changed over to the charge side when the end ofthe photosensitive paper is sent in and to the discharge side when thephotosensitive paper is in position. Push button switch 35 projecting tothe outside of case body 1 is a manual switch for a safety switchcircuit described hereinafter and switch 36 is opened and closed byoriginal hold down cover 7.

Next, as for motors I6, 20, 25, flash discharge tube 6, corona dischargedevices l7, 18 for charging, air suction mechanism 22, fan 30, heater3i, and a safety switch circuit, referring to FIG. 3, to power source 37through switch 38 there are connected in parallel with each other pilotlamp 60, fan 30, heater 31, motor 25 for developer circulating pump 26,motor 20 for carrying photosensitive papers, and air suction mechanism22. In parallel with these parts, as a safety switch circuit foroperating a high voltage generating circuit there are connected relay 40and relay switch ub-described hereinafterin series with cover switch 36closed by covering said original hold down cover 7 and said manual pushbutton switch 35. Relay 40 having relay switches 40a, 40b, 401: areopened and closed thereby. Relay switch 40a is connected to relay 40 inparallel with cover switch 36 and manual push button switch 35, andforms a self-holding circuit for relay 40. And, relay switch 40b isconnected to the high voltage power generating circuit S for lightingflash discharge tube 6, and relay switch Or is connected to the highvoltage power generating circuit H which high voltage is impressed onthe electrodes of corona discharge devices 17, 18 in charging portion D.

Usually closed relay switch 41b for the safety switch circuit is openedthrough the operation of relay 41. Power source 37 is connected torectifier 39 via power switch 38 and to one terminal 34a of change overswitch 34 connecting to condenser Q. The change over switch is operatedby the photosensitive paper on the image forming surface 10, and isconnected to the terminal 34a side while the photosensitive paper istransported therein, condenser Q is charged through the charge circuitclosed by change over switch 34 connected to terminal 34a. Condenser Qis discharged through relay 41, simultaneously the change over switch ischanged over to the other terminal 34b side by the passage of thephotosensitive paper. In the high voltage power generating circuit forlighting flash discharge lamp 6 condenser K is provided and flashdischarge tube 6 is connected in parallel therewith. Short circuitswitch 42 in parallel with condenser K is interlocked with power switch38 so as to be opened when power switch 38 is closed and closed whenpower switch 38 is opened.

Reference numeral 43 is a trigger electrode of flash discharge tube 6which is connected to high voltage generating circuit S through relayswitch 410, and closed by relay 41 when change over switch 34 is changedover to the side of contact 34b by the photosensitive paper and triggersthe discharge of flash discharge tube 6.

When power switch 38 is closed short-circuit switch 42 is opened andsimultaneously pilot lamp 60 is lit, fan 30 starts, heater 31 isexcited, motor 25 for developer circulating pump 26 is driven to pumpthe developer into developing tank 23, carrier motor 20 also starts torotate to operate conveyor 19, and air suction mechanism 22 also startsto operate, however, change over switch 34 is still on the side ofcontact 34b and accordingly condenser Q is not charged, the high voltagegenerating portion is not conductive and delivery motor 16 also is notoperated yet.

Thereupon, when original 2 is placed on glass plate 3 in originalirradiation portion A and covered with cover 7, cover switch 36 isclosed. Next, when manual switch 35 for the safety switch circuit isclosed, relay 40 is operated and is selfheld by relay switch 40a closed,and the high voltage generating circuit S for flash discharge tube 6 isclosed by relay switch 401), condenser K starts to be charged, the highvoltage generating circuit S for corona discharge devices l7, 18 isclosed by relay switch 40c, delivery motor 16 is driven through switch33, photosensitive paper delivery roller 14 interlocked with deliverymotor 16 sends out one sheet of photosensitive paper 11 fromphotosensitive paper stack C which is delivered to the charging portionby forwarding roller to receive an uniform charge onto the whole surfacethereof. The charged photosensitive paper charged is adsorbed ontoconveyor 9 by air suction mechanism 22 to be delivered to image formingsurface 10 by means of conveyor 9, and when the end of thephotosensitive paper comes into contact with the actuator of switch 33,switch 33 is opened to stop the rotation of delivery motor 16. Further,when the end of the photosensitive paper operates change over switch 34,change over switch 34 is changed over from contact 34b to contact 34a tostart to charge condenser Q. When the photosensitive paper passesthrough and is located just on image forming surface 10, change overswitch 34 is changed over from contact 34a to contact 34!) to allow thedischarge current of condenser Q to operate relay 41. And accordingly,relay switch 41b is opened, relay 40 for the safety switch circuit isdemagnetized to break its self-holding, and simultaneously relayswitches 40b, 40c are opened, so that the safety switch circuit is notclosed as long as push button switch 35 is not pushed down again andhigh voltage generating circuits 8 and H are shutoff.

The aforesaid operation of relay 41 closes relay switch 410 at the sametime to impress the trigger voltage onto trigger electrode 43 of flashdischarge tube 6 and allow condenser K to discharge into flash dischargetube 6 to emit light. The lighting time of flash discharge tube 6 isvery short, about 300 microseconds (used) or so, so that even thoughconveyor 9 is not stopped and the light image of original 2 isirradiated and accordingly its latent image is formed on thephotosensitive paper. In synchronism with the finishing of discharge ofcondenser Q relay 41 is demagnetized, and relay switch 41b is closed andrelay switch 410 is opened to return to its original position.

In the embodiment shown in FIG. 4 a switch for setting up a number ofcopying sheets is added to the embodiment described above so as to opena safety switch circuit after copying for the desired number is carriedout in succession.

ln HG. 5, index 51 on dial 50 faces scale plate 52 marked with M l 2 3and onto dial axle 53 ratchet 54 and two cam plates 48, 49 are fixedrigidly, and on cam plates 48, 49 actuators 46, 47 of dial switches 44,45 are arranged to come into contact therewith to operate dial switches44, 45 respectively. Cam plate 48 is adapted to open dial switch 44 onlywhen index 51 of the dial indicates scale 1 or M, and cam plate 49 isadapted to open dial switch 45 only when index 51 of the dial indicatesscale 1.

Reference numeral 58 denotes a solenoid for turning lever 56 pivoted onpin 57 clockwise, and pawl 55 of lever 56 turns ratchet 54 by one toothportion to turn the dial by one scale counter-clockwise.

Solenoid 58 is connected as shown in FIG. 4 in series with relay switch41c, closed by relay 41, and dial switch 44.

To the power source through relay switch 41d of relay 41 there isconnected condenser V which is charged through the operation of relay41, and when relay 4] is demagnetized the charge current of condenser Vis discharged through another relay 59 by relay switch 41d.

ln parallel with manual push button switch 35 there is formed a circuitin which dial switch 45 and relay switch 590, closed by relay 59 areconnected in series Now, provided dial 50 is set up for two copies ormore, after power switches 38 and cover switch 36 are closed, whenmanual push button switch 35 is pushed down, at the termination of thefirst copying relay 41, is operated by the discharge current ofcondenser Q to open relay switch 41b and release the self-hold of relay40 for the safety switch circuit. However, at the same time relay switch41d is changed over to the charge side to charge condenser V and insynchronization with demagnetization of relay 41 relay switch 41d ischanged over to the discharge side to operate relay 59 to close relayswitch 59a, so that manual push button switch 35 is short-circuited inparallel therewith through dial switch 45, and the safety switch circuitis closed in the same manner as push but ton 35, so as to operate relay40.

Further, through the operation of relay 4] relay switch 41c is closed tooperate solenoid 58 through dial switch 44, and accordingly by means ofpawl 55 of lever 56 ratchet 54 is turned by one tooth portion to turnthe dial to drop one step from the scale dial index. in this manner,when the scale of the dial reaches 1 dial switches 44, 45 are opened, sothat the circuit in parallel with manual push button switch 35 asdescribed above, is not closed through the operation of relay 41 andaccordingly the self-hold for the safety switch circuit by relay 40 isbroken, and the solenoid circuit is not closed and accordingly the highvoltage power generating circuit is shutoff.

Furthermore, when dial 50 is put together with scale M, dial switch 44is opened, and the dial stops without turning for every copy. On theother hand, dial switch 45 is closing so that the circuit in parallelwith push button switch 35 is closed for every copy to maintain theself-hold of relay 40 for the safety switch circuit, so as to dorepeated copying continuously until power switch 38 or cover switch 36is opened. 1n the embodiment shown in FIG. 6, condenser V, relay 59, andthe circuit in parallel with manual push button switch 35 and havingrelay contact 59a in the embodiment shown in FIG. 4, there is provided acircuit in which dial switch 45 in parallel with relay switch 41b isopened through the operation of relay 41, and normally open relay switch41d is closed through the operation of relay 41 are connected in series.As long as the dial is set up for scale M or over two the self-hold ofrelay 40 is continued and when the dial indicates scale I its self-holdis cut.

I claim:

1. A circuit for controlling an electrostatic copier having a coronaflash discharge circuit, a flash circuit for irradiating originaldocuments and a high voltage flash generating circuit and a powersource, comprising:

a manually operated switch for initiating operation of said copier,

a safety relay including an operating coil serially connected to saidmanually operated switch, said safety relay including a first contactfor maintaining current in said coil, a second contact interconnectingsaid power source with said high voltage generating source, and a thirdcontact interconnecting said power source with said corona dischargecircuit,

a first switch and a voltage storage means connected thereto, said firstswitch having a first position for connecting said voltage storage meansto said power source and a second position for actuating said flashcircuit,

a relay having an operating coil connected to said first switch in saidsecond position, a first contact actuated by the operation of saidoperating coil for releasing said safety relay, a second contact closedby the operation of said coil for the actuation of said flash circuit.

2. A circuit as in claim I wherein said relay includes third and fourthcontacts, and further comprising a second relay including a secondoperating coil and a first contact, a dial switch serially connected tosaid first contact and said first contact of said safety relay, saiddial switch and said first contact are in parallel with said manuallyoperated switch for maintaining the operativeness of said circuit duringmultiple copying,

second voltage storage means connected to said third contact wherebywith said third contact in a first position said second voltage storagemeans is connected to said second operating coil with said third contactin said first position and said voltage storage means is connected tosaid power source with said third contact in said second position andsaid first contact is opened, and

means for indicating the number of copies interconnected to said powersource through said fourth switch contact.

3. A circuit as in claim I, further comprising, a second switch seriallyconnected with said manually operated switch and closed in response tothe preparation of a document for copying at a copying station.

4. A circuit for controlling an electrostatic copier as set forth inclaim 1 further comprising:

a photosensitive paper stack, a delivery roller for delivering a sheetof photosensitive paper from said photosensitive paper stack, a deliverymotor driving said roller, and a circuit for actuating said deliverymotor in response to the closing of said manually operated switch.

5. A circuit for controlling an electrostatic copier as set forth inclaim 2 further comprising:

means for setting the number of sheets to be copied;

means for incrementally decreasing said number in response to theactuation of said flash circuit;

switching means in parallel with said manually operated switch, a thirdrelay actuated by the closing of said second contact for closing saidswitching means to maintain current in the operating coil of said safetyrelay.

6. A circuit for controlling an electrostatic copier as set forth inclaim 5 wherein said means for setting the number of sheets to be copiedincludes a numbered dial, a cam mounted to rotate with said dial andsaid switching means includes a third switch actuated by said cam withsaid dial set at I.

1. A circuit for controlling an electrostatic copier having a coronaflash discharge circuit, a flash circuit for irradiating originaldocuments and a high voltage flash generating circuit and a powersource, comprising: a manually operated switch for initiating operationof said copier, a safety relay including an operating coil seriallyconnected to said manually operated switch, said safety relay includinga first contact for maintaining current in said coil, a second contactinterconnecting said power source with said high voltage generatingsource, and a third contact interconnecting said power source with saidcorona discharge circuit, a first switch and a voltage storage meansconnected thereto, said first switch having a first position forconnecting said voltage storage means to said power source and a secondposition for actuating said flash circuit, a relay having an operatingcoil connected to said first switch in said second position, a firstcontact actuated by the operation of said operating coil for releasingsaid safety relay, a second contact closed by the operation of said coilfor the actuation of said flash circuit.
 2. A circuit as in claim 1wherein said relay includes third and fourth contacts, and furthercomprising a second relay including a second operating coil and a firstcontact, a dial switch serially connected to said first contact and saidfirst contact of said safety relay, said dial switch and said firstcontact are in parallel with said manually operated switch formaintaining the operativeness of said circuit during multiple copying,second voltage storage means connected to said third contact wherebywith said third contact in a first position said second voltage storagemeans is connected to said second operating coil with said tHird contactin said first position and said voltage storage means is connected tosaid power source with said third contact in said second position andsaid first contact is opened, and means for indicating the number ofcopies interconnected to said power source through said fourth switchcontact.
 3. A circuit as in claim 1, further comprising, a second switchserially connected with said manually operated switch and closed inresponse to the preparation of a document for copying at a copyingstation.
 4. A circuit for controlling an electrostatic copier as setforth in claim 1 further comprising: a photosensitive paper stack, adelivery roller for delivering a sheet of photosensitive paper from saidphotosensitive paper stack, a delivery motor driving said roller, and acircuit for actuating said delivery motor in response to the closing ofsaid manually operated switch.
 5. A circuit for controlling anelectrostatic copier as set forth in claim 2 further comprising: meansfor setting the number of sheets to be copied; means for incrementallydecreasing said number in response to the actuation of said flashcircuit; switching means in parallel with said manually operated switch,a third relay actuated by the closing of said second contact for closingsaid switching means to maintain current in the operating coil of saidsafety relay.
 6. A circuit for controlling an electrostatic copier asset forth in claim 5 wherein said means for setting the number of sheetsto be copied includes a numbered dial, a cam mounted to rotate with saiddial and said switching means includes a third switch actuated by saidcam with said dial set at 1.